It is well known that, in a silver halide color photographic material, many methods employ so-called dye forming couplers that react with light-sensitive silver halide emulsions and the oxidation products of aromatic primary amine developing agents to form dyes and generally a combination of a yellow coupler, a cyan coupler and a magenta coupler is used.
Of these, 5-pyrazolone type couplers, which are frequently used as a magenta coupler, have a big problem with respect to color reproduction in that the azomethine dyes obtained from these couplers exhibit a secondary peak in the region around 430 nm (the blue region) and that the red absorption of the dyes is also undesirably high.
To solve this problem, a pyrazolobenzimidazole skeleton described in British Pat. No. 1,047,612 and a pyrazolotriazole skeleton described in U.S. Pat. No. 3,725,067 have long been suggested as magenta dye image forming couplers.
Lately, a 1H-imidazo[1,2-b]pyrazole skeleton described in Japanese Patent Application (OPI) No. 162548/84 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"), a 1H-pyrazolo[1,5-b][1,2,4]triazole skeleton described in Japanese Patent Application (OPI) No. 171956/84, a 1H-pyrazolo[1,5-a]tetrazole skeleton described in Japanese Patent Application (OPI) No. 33552/85 and a 1H-pyrazolo[1,5-b]pyrazole skeleton described in Japanese Patent Application (OPI) No. 43659/85 are suggested.
However, although the above problem with respect to hue has been solved by couplers of these types, it has been found that the maximum color density (hereinafter referred to as Dmax) decreases. This is because the conversion ratio (hereinafter referred to as color forming efficiency) from the coupler to the azomethine dye when development is carried out under conditions such that a sufficient amount of an oxidation product of the aromatic primary amine developing agent will be produced in the silver halide emulsion layer.
As a means of increasing the color forming efficiency there are known means of introducing a leaving group in the coupling active site, means of adding a color development accelerator, means of changing the ballast group to one suitable to the coupler skeleton, etc.
On the other hand, with respect to color image light fastness obtained by these skeletons, although pyrazolotriazoles described in U.S. Pat. No. 3,725,067 are very unfavorable, other skeletons are excellent in color image light fastness.